// -*- Mode: C++; c-basic-offset: 2; indent-tabs-mode: nil; c-brace-offset: 0; -*-
// dviRenderer_prescan.cpp
//
// Part of KDVI - A DVI previewer for the KDE desktop environment
//
// (C) 2003--2004 Stefan Kebekus
// Distributed under the GPL

#include <config.h>

#include "dviRenderer.h"
#include "dvi.h"
#include "dviFile.h"
#include "debug_dvi.h"
#include "prebookmark.h"
#include "psgs.h"
#include "TeXFont.h"

#include <KLocalizedString>
#include <QMimeType>
#include <QMimeDatabase>
#include <kprocess.h>

#include <QApplication>
#include <QByteArray>
#include <QDir>
#include <QFileInfo>
#include <QImage>
#include <QPaintDevice>
#include <QProgressBar>
#include <QTextStream>


extern QPainter foreGroundPaint;
extern void parse_special_argument(const QString& strg, const char* argument_name, int* variable);


//#define DEBUG_PRESCAN


void dviRenderer::prescan_embedPS(char *cp, quint8 *beginningOfSpecialCommand)
{
#ifdef  DEBUG_PRESCAN
  qCDebug(OkularDviDebug) << "dviRenderer::prescan_embedPS( cp = " << cp << " ) ";
#endif

  // Encapsulated Postscript File
  if (qstrnicmp(cp, "PSfile=", 7) != 0)
    return;

  QString command = QString::fromLocal8Bit(cp+7);

  QString include_command = command.simplified();

  // The line is supposed to start with "..ile=", and then comes the
  // filename. Figure out what the filename is and stow it away. Of
  // course, this does not work if the filename contains spaces
  // (already the simplified() above is wrong). If you have
  // files like this, go away.
  QString EPSfilename = include_command;
  EPSfilename.truncate(EPSfilename.indexOf(QLatin1Char(' ')));

  // Strip enclosing quotation marks which are included by some LaTeX
  // macro packages (but not by others). This probably means that
  // graphic files are no longer found if the filename really does
  // contain quotes, but we don't really care that much.
  if ((EPSfilename.at(0) == QLatin1Char('"')) && (EPSfilename.at(EPSfilename.length()-1) == QLatin1Char('"')))
    EPSfilename = EPSfilename.mid(1,EPSfilename.length()-2);

  // Now locate the Gfx file on the hard disk...
  EPSfilename = ghostscript_interface::locateEPSfile(EPSfilename, baseURL);

  // If the file is neither a PostScript not a PDF file, we exit here.
  // The graphic file is later read when the page is rendered.
  QMimeDatabase db;
  QMimeType const mime_type =
    db.mimeTypeForFile(EPSfilename, QMimeDatabase::MatchContent);
  QString const & mime_type_name = mime_type.isValid() ? mime_type.name() : QString();

  bool const is_ps_file  = (mime_type_name == QLatin1String("application/postscript") ||
                            mime_type_name == QLatin1String("image/x-eps"));
  bool const is_pdf_file = (!is_ps_file &&
                            mime_type_name == QLatin1String("application/pdf"));
  if (!(is_ps_file || is_pdf_file))
    return;

  QString originalFName = EPSfilename;

  embedPS_progress->setLabelText(i18n("Embedding %1", EPSfilename));
  qApp->processEvents();

  // If the EPSfilename really points to a PDF file, convert that file now.
  if (is_pdf_file)
    EPSfilename = dviFile->convertPDFtoPS(EPSfilename);

  if (!QFile::exists(EPSfilename)) {
    // Find the number of the page
    quint32 currentOffset = beginningOfSpecialCommand - dviFile->dvi_Data();
    int page=0;
    for(; page < dviFile->total_pages; page++)
      if ((dviFile->page_offset[page] <= currentOffset) && (currentOffset <= dviFile->page_offset[page+1]))
        break;
    if (is_pdf_file)
      errorMsg += i18n("Page %1: The PDF file <strong>%2</strong> could not be converted to PostScript.<br>", page+1, originalFName);
    else
      errorMsg += i18n("Page %1: The PostScript file <strong>%2</strong> could not be found.<br>", page+1, originalFName);
    embedPS_progress->setValue(embedPS_progress->value()+1);
    qApp->processEvents();
    return;
  }

  // Now parse the arguments.
  int  llx     = 0;
  int  lly     = 0;
  int  urx     = 0;
  int  ury     = 0;
  int  rwi     = 0;
  int  rhi     = 0;
  int  angle   = 0;

  // just to avoid ambiguities; the filename could contain keywords
  include_command = include_command.mid(include_command.indexOf(QLatin1Char(' ')));

  parse_special_argument(include_command, "llx=", &llx);
  parse_special_argument(include_command, "lly=", &lly);
  parse_special_argument(include_command, "urx=", &urx);
  parse_special_argument(include_command, "ury=", &ury);
  parse_special_argument(include_command, "rwi=", &rwi);
  parse_special_argument(include_command, "rhi=", &rhi);
  parse_special_argument(include_command, "angle=", &angle);

  int clip=include_command.indexOf(QStringLiteral(" clip")); // -1 if clip keyword is not present, >= 0 otherwise

  // Generate the PostScript commands to be included
  QString PS = QStringLiteral("ps: @beginspecial %1 @llx %2 @lly %3 @urx %4 @ury").arg(llx).arg(lly).arg(urx).arg(ury);
  if (rwi != 0)
    PS.append( QStringLiteral(" %1 @rwi").arg(rwi) );
  if (rhi != 0)
    PS.append( QStringLiteral(" %1 @rhi").arg(rhi) );
  if (angle != 0)
    PS.append( QStringLiteral(" %1 @angle").arg(angle) );
  if (clip != -1)
    PS.append( QStringLiteral( " @clip" ));
  PS.append( QStringLiteral( " @setspecial\n" ) );

  QFile file( EPSfilename );
  if ( file.open( QIODevice::ReadOnly ) ) {
    QTextStream stream( &file );
    while ( !stream.atEnd() ) {
      PS += stream.readLine().section( QLatin1Char('%'), 0, 0);
      PS += QLatin1Char('\n');
    }
    file.close();
  }
  PS.append( QStringLiteral("@endspecial") );
  PS = PS.simplified();


  _isModified = true;
  quint32 lengthOfOldSpecial = command_pointer - beginningOfSpecialCommand;
  quint32 lengthOfNewSpecial = PS.length()+5;

  QVector<quint8> newDVI(dviFile->size_of_file + lengthOfNewSpecial-lengthOfOldSpecial);

  quint8 *commandPtrSav = command_pointer;
  quint8 *endPtrSav = end_pointer;
  end_pointer = newDVI.data() + dviFile->size_of_file + lengthOfNewSpecial-lengthOfOldSpecial;
  memcpy(newDVI.data(), dviFile->dvi_Data(), beginningOfSpecialCommand-dviFile->dvi_Data());
  command_pointer = newDVI.data()+(beginningOfSpecialCommand-dviFile->dvi_Data());
  command_pointer[0] = XXX4;
  command_pointer++;
  writeUINT32(PS.length());
  memcpy(newDVI.data()+(beginningOfSpecialCommand-dviFile->dvi_Data())+5, PS.toLatin1().constData(), PS.length() );
  memcpy(newDVI.data()+(beginningOfSpecialCommand-dviFile->dvi_Data())+lengthOfNewSpecial, beginningOfSpecialCommand+lengthOfOldSpecial,
         dviFile->size_of_file-(beginningOfSpecialCommand-dviFile->dvi_Data())-lengthOfOldSpecial );

  // Adjust page pointers in the DVI file
  dviFile->size_of_file = dviFile->size_of_file + lengthOfNewSpecial-lengthOfOldSpecial;
  end_pointer = newDVI.data() + dviFile->size_of_file;
  quint32 currentOffset = beginningOfSpecialCommand-dviFile->dvi_Data();
  for(int i=0; i < dviFile->total_pages; i++) {
    if (dviFile->page_offset[i] > currentOffset) {
      dviFile->page_offset[i] = dviFile->page_offset[i] + lengthOfNewSpecial-lengthOfOldSpecial;
      command_pointer = dviFile->page_offset[i] + newDVI.data() + 4*10 + 1;
      quint32 a = readUINT32();
      if (a > currentOffset) {
        a = a + lengthOfNewSpecial-lengthOfOldSpecial;
        command_pointer = dviFile->page_offset[i] + newDVI.data() + 4*10 + 1;
        writeUINT32(a);
      }
    }
  }

  dviFile->beginning_of_postamble            = dviFile->beginning_of_postamble + lengthOfNewSpecial - lengthOfOldSpecial;
  dviFile->page_offset[int(dviFile->total_pages)] = dviFile->beginning_of_postamble;

  command_pointer = newDVI.data() + dviFile->beginning_of_postamble + 1;
  quint32 a = readUINT32();
  if (a > currentOffset) {
    a = a + lengthOfNewSpecial - lengthOfOldSpecial;
    command_pointer = newDVI.data() + dviFile->beginning_of_postamble + 1;
    writeUINT32(a);
  }

  command_pointer = newDVI.data() + dviFile->size_of_file - 1;
  while((*command_pointer == TRAILER) && (command_pointer > newDVI.data()))
    command_pointer--;
  command_pointer -= 4;
  writeUINT32(dviFile->beginning_of_postamble);
  command_pointer -= 4;

  command_pointer = commandPtrSav;
  end_pointer     = endPtrSav;

  // Modify all pointers to point to the newly allocated memory
  command_pointer = newDVI.data() + (command_pointer - dviFile->dvi_Data()) + lengthOfNewSpecial-lengthOfOldSpecial;
  end_pointer = newDVI.data() + (end_pointer - dviFile->dvi_Data())  + lengthOfNewSpecial-lengthOfOldSpecial;

  dviFile->setNewData(newDVI);

  embedPS_progress->setValue(embedPS_progress->value()+1);
  qApp->processEvents();
  return;
}


void dviRenderer::prescan_removePageSizeInfo(char *cp, quint8 *beginningOfSpecialCommand)
{
#ifdef  DEBUG_PRESCAN
  qCDebug(OkularDviDebug) << "dviRenderer::prescan_embedPS( cp = " << cp << " ) ";
#endif

  // Encapsulated Postscript File
  if (qstrnicmp(cp, "papersize=", 10) != 0)
    return;

  for (quint8 *ptr=beginningOfSpecialCommand; ptr<command_pointer; ptr++)
    *ptr = NOP;
}


void dviRenderer::prescan_ParsePapersizeSpecial(const QString& _cp)
{
#ifdef DEBUG_PRESCAN
  qCDebug(OkularDviDebug) << "Papersize-Special : papersize" << _cp;
#endif

  QString cp = _cp.simplified();

  if (cp[0] == QLatin1Char('=')) {
    cp = cp.mid(1);
    dviFile->suggestedPageSize = new pageSize;
    dviFile->suggestedPageSize->setPageSize(cp);
  } else
    printErrorMsgForSpecials(i18n("The papersize data '%1' could not be parsed.", cp));

  return;
}


void dviRenderer::prescan_ParseBackgroundSpecial(const QString& cp)
{
  QColor col = parseColorSpecification(cp.trimmed());
  if (col.isValid())
    for(quint16 page=current_page; page < dviFile->total_pages; page++)
      PS_interface->setBackgroundColor(page, col);
  return;
}


void dviRenderer::prescan_ParseHTMLAnchorSpecial(const QString& _cp)
{
  QString cp = _cp;
  cp.truncate(cp.indexOf(QLatin1Char('"')));
  Length l;
  l.setLength_in_inch(currinf.data.dvi_v/(resolutionInDPI*shrinkfactor));
  anchorList[cp] = Anchor(current_page+1, l);
}


void dviRenderer::prescan_ParsePSHeaderSpecial(const QString& cp)
{
#ifdef DEBUG_PRESCAN
  qCDebug(OkularDviDebug) << "PostScript-special, header " << cp;
#endif

  QString _file = cp;

  // If the file is not found in the current directory, use kpsewhich
  // to find it.
  if (!QFile::exists(_file)) {
    // Otherwise, use kpsewhich to find the eps file.
    KProcess proc;
    proc << QStringLiteral("kpsewhich") << cp;
    proc.setOutputChannelMode(KProcess::SeparateChannels);
    proc.execute();
    _file = QString::fromLocal8Bit(proc.readLine().trimmed());
  }

  if (QFile::exists(_file))
    PS_interface->PostScriptHeaderString->append( QStringLiteral(" (%1) run\n").arg(_file) );
}


void dviRenderer::prescan_ParsePSBangSpecial(const QString& cp)
{
#ifdef DEBUG_PRESCAN
  qCDebug(OkularDviDebug) << "PostScript-special, literal header " << cp;
#endif

  PS_interface->PostScriptHeaderString->append( QStringLiteral( " @defspecial \n" ) );
  PS_interface->PostScriptHeaderString->append( cp );
  PS_interface->PostScriptHeaderString->append( QStringLiteral ( " @fedspecial \n" ) );
}


void dviRenderer::prescan_ParsePSQuoteSpecial(const QString& cp)
{
#ifdef DEBUG_PRESCAN
  qCCritical(OkularDviDebug) << "PostScript-special, literal PostScript " << cp;
#endif

  double PS_H = (currinf.data.dvi_h*300.0)/(65536*1200)-300;
  double PS_V = (currinf.data.dvi_v*300.0)/1200 - 300;
  PostScriptOutPutString->append( QStringLiteral(" %1 %2 moveto\n").arg(PS_H).arg(PS_V) );
  PostScriptOutPutString->append( QStringLiteral(" @beginspecial @setspecial \n") );
  PostScriptOutPutString->append( cp );
  PostScriptOutPutString->append( QStringLiteral(" @endspecial \n") );
}


void dviRenderer::prescan_ParsePSSpecial(const QString& cp)
{
#ifdef DEBUG_PRESCAN
  qCDebug(OkularDviDebug) << "PostScript-special, direct PostScript " << cp;
#endif

  // Unfortunately, in some TeX distribution the hyperref package uses
  // the dvips driver by default, rather than the hypertex driver. As
  // a result, the DVI files produced are full of PostScript that
  // specifies links and anchors, and KDVI would call the ghostscript
  // interpreter for every page which makes it really slow. This is a
  // major nuisance, so that we try to filter and interpret the
  // hypertex generated PostScript here.
  if (cp.startsWith(QLatin1String("ps:SDict begin"))) {
    // We suspect this may be hyperref generated nonsense. Let's check
    // for some known code that hyperref generates.
    if (cp == QLatin1String("ps:SDict begin H.S end"))
      return; // start of hyperref rectangle
    if (cp == QLatin1String("ps:SDict begin H.R end"))
      return; // end of hyperref rectangle
    if (cp.endsWith(QLatin1String("H.A end")))
      return; // end of hyperref anchor
    if (cp.endsWith(QLatin1String("H.L end")))
      return; // end of hyperref link
    if (cp.startsWith(QLatin1String("ps:SDict begin /product where{pop product(Distiller)")))
      return; // hyperref tries to work around Distiller bug
    if (cp.startsWith(QLatin1String("ps:SDict begin [")) && cp.endsWith(QLatin1String(" pdfmark end"))) {  // hyperref definition of link/anchor/bookmark/etc
      if (cp.contains(QStringLiteral("/DEST"))) { // The PostScript code defines an anchor
        QString anchorName = cp.section(QLatin1Char('('), 1, 1).section(QLatin1Char(')'), 0, 0);
        Length l;
        l.setLength_in_inch(currinf.data.dvi_v/(resolutionInDPI*shrinkfactor));
        anchorList[anchorName] = Anchor(current_page+1, l);
      }
      // The PostScript code defines a bookmark
      if (cp.contains(QStringLiteral("/Dest")) && cp.contains(QStringLiteral("/Title"))) {
        const QString childrenNumberAndMoreStuff = cp.section(QLatin1Char('-'), 1, 1); // Contains from the - symbol to the end of cp, effectively containing the number of children and some stuff after it
        int indexOfFirstNonDigit = 0;
        for (const QChar &c : childrenNumberAndMoreStuff) {
          if (c.isDigit()) ++indexOfFirstNonDigit;
          else break;
        }
        prebookmarks.append(PreBookmark(PDFencodingToQString(cp.section(QLatin1Char('('), 2, 2).section(QLatin1Char(')'), 0, 0)),
                                        cp.section(QLatin1Char('('), 1, 1).section(QLatin1Char(')'), 0, 0),
                                        childrenNumberAndMoreStuff.leftRef(indexOfFirstNonDigit).toUInt()
                                        ));
      }
      return;
    }
  }

  double PS_H = (currinf.data.dvi_h*300.0)/(65536*1200)-300;
  double PS_V = (currinf.data.dvi_v*300.0)/1200 - 300;

  if (cp.indexOf(QStringLiteral("ps::[begin]"), 0, Qt::CaseInsensitive) == 0) {
    PostScriptOutPutString->append( QStringLiteral(" %1 %2 moveto\n").arg(PS_H).arg(PS_V) );
    PostScriptOutPutString->append( QStringLiteral(" %1\n").arg(cp.mid(11)) );
  } else {
    if (cp.indexOf(QStringLiteral("ps::[end]"), 0, Qt::CaseInsensitive) == 0) {
      PostScriptOutPutString->append( QStringLiteral(" %1\n").arg(cp.mid(9)) );
    } else {
      if (cp.indexOf(QStringLiteral("ps::"), 0, Qt::CaseInsensitive) == 0) {
        PostScriptOutPutString->append( QStringLiteral(" %1\n").arg(cp.mid(4)) );
      } else {
        PostScriptOutPutString->append( QStringLiteral(" %1 %2 moveto\n").arg(PS_H).arg(PS_V) );
        PostScriptOutPutString->append( QStringLiteral(" %1\n").arg(cp.mid(3)) );
      }
    }
  }
}


void dviRenderer::prescan_ParsePSFileSpecial(const QString& cp)
{
#ifdef DEBUG_PRESCAN
  qCDebug(OkularDviDebug) << "epsf-special: psfile=" << cp;
#endif

  QString include_command = cp.simplified();

  // The line is supposed to start with "..ile=", and then comes the
  // filename. Figure out what the filename is and stow it away. Of
  // course, this does not work if the filename contains spaces
  // (already the simplified() above is wrong). If you have
  // files like this, go away.
  QString EPSfilename = include_command;
  EPSfilename.truncate(EPSfilename.indexOf(QLatin1Char(' ')));

  // Strip enclosing quotation marks which are included by some LaTeX
  // macro packages (but not by others). This probably means that
  // graphic files are no longer found if the filename really does
  // contain quotes, but we don't really care that much.
  if ((EPSfilename.at(0) == QLatin1Char('\"')) && (EPSfilename.at(EPSfilename.length()-1) == QLatin1Char('\"'))) {
    EPSfilename = EPSfilename.mid(1,EPSfilename.length()-2);
  }

  // If the file name ends in 'png', 'gif', 'jpg' or 'jpeg', we assume
  // that this is NOT a PostScript file, and we exit here.
  QString ending = EPSfilename.section(QLatin1Char('.'), -1).toLower();
  if ((ending == QLatin1String("png")) || (ending == QLatin1String("gif")) || (ending == QLatin1String("jpg")) || (ending == QLatin1String("jpeg"))) {
    dviFile->numberOfExternalNONPSFiles++;
    return;
  }

  // Now assume that the graphics file *is* a PostScript file
  dviFile->numberOfExternalPSFiles++;

  // Now locate the Gfx file on the hard disk...
  EPSfilename = ghostscript_interface::locateEPSfile(EPSfilename, baseURL);

  // If the EPSfilename really points to a PDF file, convert that file now.
  if (ending == QLatin1String("pdf")) {
    QString convErrorMsg;
    EPSfilename = dviFile->convertPDFtoPS(EPSfilename, &convErrorMsg);
    if (convErrorMsg.isEmpty() != true) {
      emit error(convErrorMsg, -1);
      return;
    }
  }

  // Now parse the arguments.
  int  llx     = 0;
  int  lly     = 0;
  int  urx     = 0;
  int  ury     = 0;
  int  rwi     = 0;
  int  rhi     = 0;
  int  angle   = 0;

  // just to avoid ambiguities; the filename could contain keywords
  include_command = include_command.mid(include_command.indexOf(QLatin1Char(' ')));

  parse_special_argument(include_command, "llx=", &llx);
  parse_special_argument(include_command, "lly=", &lly);
  parse_special_argument(include_command, "urx=", &urx);
  parse_special_argument(include_command, "ury=", &ury);
  parse_special_argument(include_command, "rwi=", &rwi);
  parse_special_argument(include_command, "rhi=", &rhi);
  parse_special_argument(include_command, "angle=", &angle);

  int clip=include_command.indexOf(QStringLiteral(" clip")); // -1 if clip keyword is not present, >= 0 otherwise

  if (QFile::exists(EPSfilename)) {
    double PS_H = (currinf.data.dvi_h*300.0)/(65536*1200)-300;
    double PS_V = (currinf.data.dvi_v*300.0)/1200 - 300;
    PostScriptOutPutString->append( QStringLiteral(" %1 %2 moveto\n").arg(PS_H).arg(PS_V) );
    PostScriptOutPutString->append( QStringLiteral("@beginspecial ") );
    PostScriptOutPutString->append( QStringLiteral(" %1 @llx").arg(llx) );
    PostScriptOutPutString->append( QStringLiteral(" %1 @lly").arg(lly) );
    PostScriptOutPutString->append( QStringLiteral(" %1 @urx").arg(urx) );
    PostScriptOutPutString->append( QStringLiteral(" %1 @ury").arg(ury) );
    if (rwi != 0)
      PostScriptOutPutString->append( QStringLiteral(" %1 @rwi").arg(rwi) );
    if (rhi != 0)
      PostScriptOutPutString->append( QStringLiteral(" %1 @rhi").arg(rhi) );
    if (angle != 0)
      PostScriptOutPutString->append( QStringLiteral(" %1 @angle").arg(angle) );
    if (clip != -1)
      PostScriptOutPutString->append( QStringLiteral(" @clip"));
    PostScriptOutPutString->append( QStringLiteral(" @setspecial \n") );
    PostScriptOutPutString->append( QStringLiteral(" (%1) run\n").arg(EPSfilename) );
    PostScriptOutPutString->append( QStringLiteral("@endspecial \n") );
  }

  return;
}


void dviRenderer::prescan_ParseSourceSpecial(const QString& cp)
{
  // if no rendering takes place, i.e. when the DVI file is first
  // loaded, generate a DVI_SourceFileAnchor. These anchors are used
  // in forward search, i.e. to relate references line
  // "src:123file.tex" to positions in the DVI file

  // extract the file name and the numeral part from the string
  qint32 j;
  for(j=0;j<cp.length();j++)
    if (!cp.at(j).isNumber())
      break;
  quint32 sourceLineNumber = cp.leftRef(j).toUInt();
  QFileInfo fi1(dviFile->filename);
  QString  sourceFileName   = QFileInfo(fi1.dir(), cp.mid(j).trimmed()).absoluteFilePath();
  Length l;
  l.setLength_in_inch(currinf.data.dvi_v/(resolutionInDPI*shrinkfactor));
  DVI_SourceFileAnchor sfa(sourceFileName, sourceLineNumber, current_page+1, l);
  sourceHyperLinkAnchors.push_back(sfa);
}


void dviRenderer::prescan_parseSpecials(char *cp, quint8 *)
{
  QString special_command = QString::fromUtf8(cp);

  // Now to those specials which are only interpreted during the
  // prescan phase, and NOT during rendering.

  // PaperSize special
  if (qstrnicmp(cp, "papersize", 9) == 0) {
    prescan_ParsePapersizeSpecial(special_command.mid(9));
    return;
  }

  // color special for background color
  if (qstrnicmp(cp, "background", 10) == 0) {
    prescan_ParseBackgroundSpecial(special_command.mid(10));
    return;
  }

  // HTML anchor special
  if (qstrnicmp(cp, "html:<A name=", 13) == 0) {
    prescan_ParseHTMLAnchorSpecial(special_command.mid(14));
    return;
  }

  // Postscript Header File
  if (qstrnicmp(cp, "header=", 7) == 0) {
    prescan_ParsePSHeaderSpecial(special_command.mid(7));
    return;
  }

  // Literal Postscript Header
  if (cp[0] == '!') {
    prescan_ParsePSBangSpecial(special_command.mid(1));
    return;
  }

  // Literal Postscript inclusion
  if (cp[0] == '"') {
    prescan_ParsePSQuoteSpecial(special_command.mid(1));
    return;
  }

  // PS-Postscript inclusion
  if (qstrnicmp(cp, "ps:", 3) == 0) {
    prescan_ParsePSSpecial(special_command);
    return;
  }

  // Encapsulated Postscript File
  if (qstrnicmp(cp, "PSfile=", 7) == 0) {
    prescan_ParsePSFileSpecial(special_command.mid(7));
    return;
  }

  // source special
  if (qstrnicmp(cp, "src:", 4) == 0) {
    prescan_ParseSourceSpecial(special_command.mid(4));
    return;
  }

  // Finally there are those special commands which must be considered
  // both during rendering and during the pre-scan phase

  // HTML anchor end
  if (qstrnicmp(cp, "html:</A>", 9) == 0) {
    html_anchor_end();
    return;
  }

  return;
}


void dviRenderer::prescan_setChar(unsigned int ch)
{
  TeXFontDefinition *fontp = currinf.fontp;
  if (fontp == nullptr)
    return;

  if (currinf.set_char_p == &dviRenderer::set_char) {
    glyph *g = ((TeXFont *)(currinf.fontp->font))->getGlyph(ch, true, globalColor);
    if (g == nullptr)
      return;
    currinf.data.dvi_h += (int)(currinf.fontp->scaled_size_in_DVI_units * dviFile->getCmPerDVIunit() *
                                (1200.0 / 2.54)/16.0 * g->dvi_advance_in_units_of_design_size_by_2e20 + 0.5);
    return;
  }

  if (currinf.set_char_p == &dviRenderer::set_vf_char) {
    macro *m = &currinf.fontp->macrotable[ch];
    if (m->pos == nullptr)
      return;
    currinf.data.dvi_h += (int)(currinf.fontp->scaled_size_in_DVI_units * dviFile->getCmPerDVIunit() *
                                (1200.0 / 2.54)/16.0 * m->dvi_advance_in_units_of_design_size_by_2e20 + 0.5);
    return;
  }
}


void dviRenderer::prescan(parseSpecials specialParser)
{
#ifdef DEBUG_PRESCAN
  qCDebug(OkularDviDebug) << "dviRenderer::prescan( ... )";
#endif

  if (resolutionInDPI == 0.0)
    setResolution(100);

  qint32 RRtmp=0, WWtmp=0, XXtmp=0, YYtmp=0, ZZtmp=0;
  quint8 ch;
  double fontPixelPerDVIunit = dviFile->getCmPerDVIunit() * 1200.0/2.54;

  stack.clear();

  currinf.fontp        = nullptr;
  currinf.set_char_p   = &dviRenderer::set_no_char;

  for (;;) {
    ch = readUINT8();

    if (ch <= (unsigned char) (SETCHAR0 + 127)) {
      prescan_setChar(ch);
      continue;
    }

    if (FNTNUM0 <= ch && ch <= (unsigned char) (FNTNUM0 + 63)) {
      currinf.fontp = currinf.fonttable->value(ch - FNTNUM0);
      if (currinf.fontp == nullptr) {
        errorMsg = i18n("The DVI code referred to font #%1, which was not previously defined.", ch - FNTNUM0);
        return;
      }
      currinf.set_char_p = currinf.fontp->set_char_p;
      continue;
    }


    qint32 a, b;

    switch (ch) {
    case SET1:
      prescan_setChar(readUINT8());
      break;

    case SETRULE:
      /* Be careful, dvicopy outputs rules with height =
         0x80000000. We don't want any SIGFPE here. */
      a = readUINT32();
      b = readUINT32();
      b = ((long) (b *  65536.0*fontPixelPerDVIunit));
      currinf.data.dvi_h += b;
      break;

    case PUTRULE:
      a = readUINT32();
      b = readUINT32();
      break;

    case PUT1:
    case NOP:
      break;

    case BOP:
      command_pointer += 11 * 4;
      currinf.data.dvi_h = 1200 << 16; // Reminder: DVI-coordinates start at (1",1") from top of page
      currinf.data.dvi_v = 1200;
      currinf.data.pxl_v = int(currinf.data.dvi_v/shrinkfactor);
      currinf.data.w = currinf.data.x = currinf.data.y = currinf.data.z = 0;
      break;

    case PUSH:
      stack.push(currinf.data);
      break;

    case POP:
      if (stack.isEmpty())
        return;
      else
        currinf.data = stack.pop();
      break;

    case RIGHT1:
    case RIGHT2:
    case RIGHT3:
    case RIGHT4:
      RRtmp = readINT(ch - RIGHT1 + 1);
      currinf.data.dvi_h += ((long) (RRtmp *  65536.0*fontPixelPerDVIunit));
      break;

    case W1:
    case W2:
    case W3:
    case W4:
      WWtmp = readINT(ch - W0);
      currinf.data.w = ((long) (WWtmp *  65536.0*fontPixelPerDVIunit));
      // fallthrough
    case W0:
      currinf.data.dvi_h += currinf.data.w;
      break;

    case X1:
    case X2:
    case X3:
    case X4:
      XXtmp = readINT(ch - X0);
      currinf.data.x = ((long) (XXtmp *  65536.0*fontPixelPerDVIunit));
      // fallthrough
    case X0:
      currinf.data.dvi_h += currinf.data.x;
      break;

    case DOWN1:
    case DOWN2:
    case DOWN3:
    case DOWN4:
      {
        qint32 DDtmp = readINT(ch - DOWN1 + 1);
        currinf.data.dvi_v += ((long) (DDtmp *  65536.0*fontPixelPerDVIunit))/65536;
        currinf.data.pxl_v  = int(currinf.data.dvi_v/shrinkfactor);
      }
      break;

    case Y1:
    case Y2:
    case Y3:
    case Y4:
      YYtmp = readINT(ch - Y0);
      currinf.data.y    = ((long) (YYtmp *  65536.0*fontPixelPerDVIunit));
      // fallthrough
    case Y0:
      currinf.data.dvi_v += currinf.data.y/65536;
      currinf.data.pxl_v = int(currinf.data.dvi_v/shrinkfactor);
      break;

    case Z1:
    case Z2:
    case Z3:
    case Z4:
      ZZtmp = readINT(ch - Z0);
      currinf.data.z    = ((long) (ZZtmp *  65536.0*fontPixelPerDVIunit));
      // fallthrough
    case Z0:
      currinf.data.dvi_v += currinf.data.z/65536;
      currinf.data.pxl_v  = int(currinf.data.dvi_v/shrinkfactor);
      break;

    case FNT1:
    case FNT2:
    case FNT3:
    case FNT4:
      currinf.fontp = currinf.fonttable->value(readUINT(ch - FNT1 + 1));
      if (currinf.fontp == nullptr)
        return;
      currinf.set_char_p = currinf.fontp->set_char_p;
      break;

    case XXX1:
    case XXX2:
    case XXX3:
    case XXX4:
      {
        quint8 *beginningOfSpecialCommand = command_pointer-1;
        a = readUINT(ch - XXX1 + 1);
        if (a > 0) {
          char        *cmd        = new char[a+1];
          strncpy(cmd, (char *)command_pointer, a);
          command_pointer += a;
          cmd[a] = '\0';
          (this->*specialParser)(cmd, beginningOfSpecialCommand);
          delete [] cmd;
        }
      }
      break;

    case FNTDEF1:
    case FNTDEF2:
    case FNTDEF3:
    case FNTDEF4:
      command_pointer += 12 + ch - FNTDEF1 + 1;
      command_pointer += readUINT8() + readUINT8();
      break;

    default:
      return;
    } /* end switch */
  } /* end for */
}
